Improvement in casting valve-chambers and seats



aware am over JOHN K. *BU-RRE, or `Routern sarna, new ronn.

LettersIateiit` No. 107,867, dated October 4, 1870.

The Schedule referred to inthese Letters Patent and making partof thesama I, JOHN K. BURKE, of Rochester, in the conntyof i Monroeiand Stateof .New York, have invented a ce1- iainmproved Method of CastingValve-Chambers x Yand Seats, of which the following is a specication.

My invention relates to a peculiar method of introducing apreviously-made valve-seat or seats into the i 1 shell of `theirchambersduring the process of casting.4

It iswell known that in the `use of steam and other valves where astream of nid Orliquid, at a high pressure, `ispassing rapidly, theseats or bearings ,ofl

` the valves soonbecomegrooved or cnt outlbysuch action, renderingithemuseless tilly repaired. 'ilhis `is particularly the case withsteam-governors and throt- `tlc-valves, in which seats are formed uponinternal portions `of theshell, since it is difficult, and` sometimesimpossible tofcast such shells ,soas to leave the seats of the requisitedegree of hardness, and expensive, moreover, to introduce separate seatsby any of the ordinary. methods.

g i In the accompyaning drawing I have represented my invention asapliiliedto` the casting of agovernor'- globe vor shell,'but it `isequally valuable in a large class of `similar `constructions.`

i `Figure lisa vertical section-'of a governor-globe andvalve-seats.

` Figure 2 is a sectional elevation of -the core.' Figure 3 shows amodification of the latter. The rings orV valve-seats a are previously'prepared from metal of the requisite degree of hardness, bored i out,or` otherwise made of proper size,.a`nd placedinpon the core A, iig.2,`so as to -be supportedin suitable y i 4positions in the mold duringtheprocess of casting.

. .Since, however, in nearly all vvalve-chambers, it is necessary toprovide recesses, b, tig. 1, upon one or both sides of .the seat, forthe purpose of limiting 'thelengthof t bearing of the valve, and,consequently,- to make the core larger at those points, as shown at b',tig.` 2, itis V obviously impracticable to place the rings upon acore ofordinary formation.

` ,'lo obviate this ldiiicultygl make the core A in two or moresections, according tothe number of valve-seats introduced, the portionbr forming the recesses b, being in the formofa hollow cylinder, and

" sliding `over the portion of thecore designed to receive it,asindicated in tlg. 2. rDhus the ring or seat a, the internal diameterof which corresponds to the external diameter of the core at that pointmay be placedup- 0n vthe core in its proper position, the section bpushed ou behind it, and the whole laid in the mold. After casting, itis plain that the core can be removed in the usual manner, while themetallic ring remains in and forms that portion of the shellconstituting the valve-seat.

fAn equivalentlplan, by which the same object is accomplished, is shownin fig. 3, in which the entire end c of the core is made separately fromthe central the ring in the same position as before, and' held in placeby a rod, d,`passing through the whole. This plan, however, is moreexpensive, and not so uniformly sure to produce good castings as theformer.

`The periphery of the seats a may bc provided with grooves or ledges,f0r the purpose'of obtaininga more secure attachment to the metal of theshell. In practice, no difficulty is found inthe leakage of the fluidaround the seat-s, since the metal soon becomes oxidized in the4 joint,and the latter thus perfectly closed. vBy my invention I obtain thefollowing advantages:

' The expense of vcasting the shells and seats is but little' more thanby the lold method, while the danger of losing castings 'by' flawsis-largelylreduced; the

seats may be made of metal of' any degree of hardness, and bored ont`nearly to the requisite size before fbeing introduced into the mold,thus giving the worlti man an opportunity to` detect iiaws, which,however, are far less liable to occur than when cast' with the shell;the process of boring, in the manner just described, is less expensivethan by the usual method.

What I claimas m'y invention isvThe method ot'castng the shells ofvalve-chambers by means of a core, upon which is placedanl annularmetallic seat or seats, to be left in such shells, for the `purposes setforth. JOI-1N K. BURKE.

Witnesses:

D. L. JOHNSTON, I ILOLnMENT.

